A word from Sunzoe, the 'The Munster's have their very own Wednesday Addams' costume creator:

Mom, dad, brother, and baby sister.
Cousin IT: Hair from local wig store hot clued to a very large pillowcase. The hat was purchased online and hair is glued to the hat as well. This costume is very hot and heavy. Black dress shoes. In order to hot glue use the additional pillowcase to tie in the middle of each hair piece then hot clue only the fabric from each to each other; never the hair. Glasses from the local store.
Frankenstein and Bride of Frankenstein were purchased at a Halloween store in Dallas Texas and pieced together: His pants, shoes, and face paint and Her dress: large petty coat and old-fashioned wedding night robe. Used black shirt for underneath and girdle came from Cindy's. Shoes previously owned. Her facepaint from Walmart and wig store. Both adults hair is spray painted black and black and white. Brides hair has a 7 up bottle inside to hold form - tutorials are on youtube. His dresscoat came from Burlington Coat Factory and black shirt from Target. His bolts came from Walmart.
Baby has hair extension clips from local wig store. dress and tights came from Target and white felt was used for the collar. white buttons for her dress came from Hobby Lobby. Her shoes were previously owned.
Total cost for all costumes was around #1000.00